Re: [LAD] Calculate R M S

On Fri, 18 Feb 2011 21:20:15 +0000
Fons Adriaensen <fons@email-addr-hidden> wrote:

> On Fri, Feb 18, 2011 at 11:30:24AM -0800, Mark Knecht wrote:
> > On Wed, Feb 16, 2011 at 10:45 AM, Fons Adriaensen <fons@email-addr-hidden> wrote:
> > <SNIP>
> > >
> > > Some filtering followed by RMS detection will provide a good
> > > approximation to subjective loudness.
> > >
> > <SNIP>
> >
> > Is this part to implement something like like Fletcher-Munson curves?
>
> In general that is not the case, probably because for most types of
> content the mid-frequency range is dominant. And loudness measuring
> systems are expected to give good results for typical content, not
> to estimate the subjective loudness of single tones or narrow band
> signals.
>
> The filter recommended by the ITU and EBU is a combination of a 2nd
> order highpass (around 50 Hz) and a shelf filter providing 4 dB gain
> at 4 kHz and above. Listening tests have shown this to work quite
> well in practice.
>
> Ciao,

Interesting. Where do they roll off the top end? Or don't they say?

-- 
Will J Godfrey
http://www.musically.me.uk
Say you have a poem and I have a tune.
Exchange them and we can both have a poem, a tune, and a song.
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